Treatment-of-Landfill-Leachate-by-Constructed

IntroductionTreatmentoflandfillleachatehasbecomeoneofthemostimportantenvironmentalproblemsduetofluctuatingcompositionandquantityaswellashighconcentrationsofspecificpollutants(polycyclicaromatichydrocarbonsPAH,absorbableorganichalogensAOX,polychlorinatedbiphenylsPCB,heavymetals)andveryhighammonianitrogenandCODconcentrations.Considerablevariationsinthequalityofleachatefromdifferentlandfillshasbeenreportedintheliterature[1].Theleachatefromyoungland-fills(wheretheacetogenicbiodegradationphaseisactive)ischaracterizedbyhighchemicaloxygendemand(COD),biologicaloxygendemand(BOD),andNa+,Cl¯andNH4+content,whiletheleachateproducedinthesubsequentmethanogenicphaseischaracterizedbyrelativelylowCOD,BOD,andNH4+contentandhigherpH[2,3].Thecompositionofleachatesfrom35landfillsiteswithaceto-genicand29withmethanogenicconditionsgivenbytheBritishDepartmentoftheEnvironment(1995)iscitedbyJonesetal.[2].TheaverageCODandBODvaluesfor“ace-togenic”leachateswere36,817mgO2/l(therange2,740-152,000)and18,632(therange2,000-68,000)mgO2/l,PolishJ.ofEnviron.Stud.Vol.19,No.3(2010),643-650OriginalResearchTreatmentofLandfillLeachatebyConstructedWetlands:ThreeCaseStudiesEwaWojciechowska,MagdalenaGajewska,HannaObarska-PempkowiakFacultyofCivilandEnvironmentalEngineering,GdańskUniversityofTechnology,Narutowicza11/12,80-952Gdańsk,PolandReceived:1October2009Accepted:4January2010AbstractTheperformanceofthreeconstructedwetlandsystemstreatinglandfillleachate,twolocatedinnorth-ernPoland(SzadółkinearGdańskandGatkanearMiastko)andoneinsouthernSweden(Örebro),isdis-cussed.TheCWsdifferinsize,hydraulicregime,typeofhydrophyticplants,andtypeofleachatepre-treat-mentbeforedischargingtotheCW.TheCWinSzadółkiconsistsoftwoparallelbedswithsub-surface,hori-zontalflowofleachate(HSSF)plantedwithreed.TheleachateisdischargedtotheCWwithoutpre-treatment.ThefacilityinGatkaisawillowplantationthatreceivesleachateafterpreliminarysedimentationinareten-tionpond.ThesystematÖrebroconsistsofaseriesofpondswithasurfaceflowofleachate(thefreewatersurfac